Catalytic domain of Cell division control protein 7-like Protein Serine/Threonine Kinases. Serine/threonine kinases (STKs), (Cdc7)-like subfamily, catalytic (c) domain. STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. The Cdc7-like subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase. Members of this subfamily include Schizosaccharomyces pombe Cdc7, Saccharomyces cerevisiae Cdc15, Arabidopsis thaliana mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK) epsilon, and related proteins. MAPKKKs phosphorylate and activate MAPK kinases (MAPKKs or MKKs or MAP2Ks), which in turn phosphorylate and activate MAPKs during signaling cascades that are important in mediating cellular responses to extracellular signals. Fission yeast Cdc7 is essential for cell division by playing a key role in the initiation of septum formation and cytokinesis. Budding yeast Cdc15 functions to coordinate mitotic exit with cytokinesis. Arabidopsis MAPKKK epsilon is required for pollen development in the plasma membrane.